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SubjectRe: [PATCH V13 12/12] PCI: tegra: Add Tegra194 PCIe support
On Wed, Jul 10, 2019 at 11:52:12AM +0530, Vidya Sagar wrote:

[...]

> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> new file mode 100644
> index 000000000000..189779edd976
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -0,0 +1,1632 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * PCIe host controller driver for Tegra194 SoC
> + *
> + * Copyright (C) 2019 NVIDIA Corporation.
> + *
> + * Author: Vidya Sagar <vidyas@nvidia.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/debugfs.h>
> +#include <linux/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/iopoll.h>
> +#include <linux/kernel.h>
> +#include <linux/kfifo.h>
> +#include <linux/kthread.h>

What do you need these two headers for ?

[...]

> +struct tegra_pcie_dw {
> + struct device *dev;
> + struct resource *appl_res;
> + struct resource *dbi_res;
> + struct resource *atu_dma_res;
> + void __iomem *appl_base;
> + struct clk *core_clk;
> + struct reset_control *core_apb_rst;
> + struct reset_control *core_rst;
> + struct dw_pcie pci;
> + enum dw_pcie_device_mode mode;
> + struct tegra_bpmp *bpmp;
> +
> + bool supports_clkreq;
> + bool enable_cdm_check;
> + u8 init_link_width;
> + bool link_state;
> + u32 msi_ctrl_int;
> + u32 num_lanes;
> + u32 max_speed;
> + u32 cid;
> + bool update_fc_fixup;
> + u32 cfg_link_cap_l1sub;
> + u32 pcie_cap_base;
> + u32 aspm_cmrt;
> + u32 aspm_pwr_on_t;
> + u32 aspm_l0s_enter_lat;o

Nit: You should try to group variables according to their usage,
it would make sense to group booleans together.

> + struct regulator *pex_ctl_supply;
> +
> + unsigned int phy_count;
> + struct phy **phys;
> +
> + struct dentry *debugfs;
> +};
> +
> +static inline struct tegra_pcie_dw *to_tegra_pcie(struct dw_pcie *pci)
> +{
> + return container_of(pci, struct tegra_pcie_dw, pci);
> +}
> +
> +static inline void appl_writel(struct tegra_pcie_dw *pcie, const u32 value,
> + const u32 reg)
> +{
> + writel_relaxed(value, pcie->appl_base + reg);
> +}
> +
> +static inline u32 appl_readl(struct tegra_pcie_dw *pcie, const u32 reg)
> +{
> + return readl_relaxed(pcie->appl_base + reg);
> +}
> +
> +struct tegra_pcie_soc {
> + enum dw_pcie_device_mode mode;
> +};
> +
> +static void apply_bad_link_workaround(struct pcie_port *pp)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> + struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> + u32 current_link_width;
> + u16 val;
> +
> + /*
> + * NOTE:- Since this scenario is uncommon and link as such is not
> + * stable anyway, not waiting to confirm if link is really
> + * transitioning to Gen-2 speed
> + */
> + val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> + if (val & PCI_EXP_LNKSTA_LBMS) {
> + current_link_width = (val & PCI_EXP_LNKSTA_NLW) >>
> + PCI_EXP_LNKSTA_NLW_SHIFT;
> + if (pcie->init_link_width > current_link_width) {
> + dev_warn(pci->dev, "PCIe link is bad, width reduced\n");
> + val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> + PCI_EXP_LNKCTL2);
> + val &= ~PCI_EXP_LNKCTL2_TLS;
> + val |= PCI_EXP_LNKCTL2_TLS_2_5GT;
> + dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
> + PCI_EXP_LNKCTL2, val);
> +
> + val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> + PCI_EXP_LNKCTL);
> + val |= PCI_EXP_LNKCTL_RL;
> + dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
> + PCI_EXP_LNKCTL, val);
> + }
> + }
> +}
> +
> +static irqreturn_t tegra_pcie_rp_irq_handler(struct tegra_pcie_dw *pcie)
> +{
> + struct dw_pcie *pci = &pcie->pci;
> + struct pcie_port *pp = &pci->pp;
> + u32 val, tmp;
> + u16 val_w;
> +
> + val = appl_readl(pcie, APPL_INTR_STATUS_L0);
> + if (val & APPL_INTR_STATUS_L0_LINK_STATE_INT) {
> + val = appl_readl(pcie, APPL_INTR_STATUS_L1_0_0);
> + if (val & APPL_INTR_STATUS_L1_0_0_LINK_REQ_RST_NOT_CHGED) {
> + appl_writel(pcie, val, APPL_INTR_STATUS_L1_0_0);
> +
> + /* SBR & Surprise Link Down WAR */
> + val = appl_readl(pcie, APPL_CAR_RESET_OVRD);
> + val &= ~APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
> + appl_writel(pcie, val, APPL_CAR_RESET_OVRD);
> + udelay(1);
> + val = appl_readl(pcie, APPL_CAR_RESET_OVRD);
> + val |= APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
> + appl_writel(pcie, val, APPL_CAR_RESET_OVRD);
> +
> + val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
> + val |= PORT_LOGIC_GEN2_CTRL_DIRECT_SPEED_CHANGE;
> + dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
> + }
> + }
> +
> + if (val & APPL_INTR_STATUS_L0_INT_INT) {
> + val = appl_readl(pcie, APPL_INTR_STATUS_L1_8_0);
> + if (val & APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS) {
> + appl_writel(pcie,
> + APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS,
> + APPL_INTR_STATUS_L1_8_0);
> + apply_bad_link_workaround(pp);
> + }
> + if (val & APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS) {
> + appl_writel(pcie,
> + APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS,
> + APPL_INTR_STATUS_L1_8_0);
> +
> + val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> + PCI_EXP_LNKSTA);
> + dev_dbg(pci->dev, "Link Speed : Gen-%u\n", val_w &
> + PCI_EXP_LNKSTA_CLS);
> + }
> + }
> +
> + val = appl_readl(pcie, APPL_INTR_STATUS_L0);
> + if (val & APPL_INTR_STATUS_L0_CDM_REG_CHK_INT) {
> + val = appl_readl(pcie, APPL_INTR_STATUS_L1_18);
> + tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS);
> + if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMPLT) {
> + dev_info(pci->dev, "CDM check complete\n");
> + tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPLETE;
> + }
> + if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMP_ERR) {
> + dev_err(pci->dev, "CDM comparison mismatch\n");
> + tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPARISON_ERROR;
> + }
> + if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_LOGIC_ERR) {
> + dev_err(pci->dev, "CDM Logic error\n");
> + tmp |= PCIE_PL_CHK_REG_CHK_REG_LOGIC_ERROR;
> + }
> + dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS, tmp);
> + tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_ERR_ADDR);
> + dev_err(pci->dev, "CDM Error Address Offset = 0x%08X\n", tmp);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t tegra_pcie_irq_handler(int irq, void *arg)
> +{
> + struct tegra_pcie_dw *pcie = arg;
> +
> + if (pcie->mode == DW_PCIE_RC_TYPE)
> + return tegra_pcie_rp_irq_handler(pcie);

What's the point of registering the handler if mode != DW_PCIE_RC_TYPE ?

> + return IRQ_NONE;
> +}
> +
> +static int tegra_pcie_dw_rd_own_conf(struct pcie_port *pp, int where, int size,
> + u32 *val)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +
> + /*
> + * This is an endpoint mode specific register happen to appear even
> + * when controller is operating in root port mode and system hangs
> + * when it is accessed with link being in ASPM-L1 state.
> + * So skip accessing it altogether
> + */
> + if (where == PORT_LOGIC_MSIX_DOORBELL) {
> + *val = 0x00000000;
> + return PCIBIOS_SUCCESSFUL;
> + }
> +
> + return dw_pcie_read(pci->dbi_base + where, size, val);
> +}
> +
> +static int tegra_pcie_dw_wr_own_conf(struct pcie_port *pp, int where, int size,
> + u32 val)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +
> + /*
> + * This is an endpoint mode specific register happen to appear even
> + * when controller is operating in root port mode and system hangs
> + * when it is accessed with link being in ASPM-L1 state.
> + * So skip accessing it altogether
> + */
> + if (where == PORT_LOGIC_MSIX_DOORBELL)
> + return PCIBIOS_SUCCESSFUL;
> +
> + return dw_pcie_write(pci->dbi_base + where, size, val);
> +}
> +
> +#if defined(CONFIG_PCIEASPM)
> +static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
> +{
> + u32 val;
> +
> + val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
> + val &= ~PCI_L1SS_CAP_ASPM_L1_1;
> + dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
> +}
> +
> +static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
> +{
> + u32 val;
> +
> + val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
> + val &= ~PCI_L1SS_CAP_ASPM_L1_2;
> + dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
> +}
> +
> +static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
> +{
> + u32 val;
> +
> + val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid]);
> + val &= ~(EVENT_COUNTER_EVENT_SEL_MASK << EVENT_COUNTER_EVENT_SEL_SHIFT);
> + val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> + val |= event << EVENT_COUNTER_EVENT_SEL_SHIFT;
> + val |= EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> + dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
> + val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_data_offset[pcie->cid]);
> + return val;
> +}
> +
> +static int aspm_state_cnt(struct seq_file *s, void *data)
> +{
> + struct tegra_pcie_dw *pcie = (struct tegra_pcie_dw *)
> + dev_get_drvdata(s->private);
> + u32 val;
> +
> + seq_printf(s, "Tx L0s entry count : %u\n",
> + event_counter_prog(pcie, EVENT_COUNTER_EVENT_Tx_L0S));
> +
> + seq_printf(s, "Rx L0s entry count : %u\n",
> + event_counter_prog(pcie, EVENT_COUNTER_EVENT_Rx_L0S));
> +
> + seq_printf(s, "Link L1 entry count : %u\n",
> + event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1));
> +
> + seq_printf(s, "Link L1.1 entry count : %u\n",
> + event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_1));
> +
> + seq_printf(s, "Link L1.2 entry count : %u\n",
> + event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_2));
> +
> + /* Clear all counters */
> + dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid],
> + EVENT_COUNTER_ALL_CLEAR);
> +
> + /* Re-enable counting */
> + val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> + val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> + dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
> +
> + return 0;
> +}
> +#endif
> +
> +static int init_debugfs(struct tegra_pcie_dw *pcie)
> +{
> +#if defined(CONFIG_PCIEASPM)
> + struct dentry *d;
> +
> + d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
> + pcie->debugfs, aspm_state_cnt);
> + if (IS_ERR_OR_NULL(d))
> + dev_err(pcie->dev,
> + "Failed to create debugfs file \"aspm_state_cnt\"\n");
> +#endif
> + return 0;
> +}
> +
> +static void tegra_pcie_enable_system_interrupts(struct pcie_port *pp)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> + struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> + u32 val;
> + u16 val_w;
> +
> + val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> + val |= APPL_INTR_EN_L0_0_LINK_STATE_INT_EN;
> + appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +
> + val = appl_readl(pcie, APPL_INTR_EN_L1_0_0);
> + val |= APPL_INTR_EN_L1_0_0_LINK_REQ_RST_NOT_INT_EN;
> + appl_writel(pcie, val, APPL_INTR_EN_L1_0_0);
> +
> + if (pcie->enable_cdm_check) {
> + val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> + val |= APPL_INTR_EN_L0_0_CDM_REG_CHK_INT_EN;
> + appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +
> + val = appl_readl(pcie, APPL_INTR_EN_L1_18);
> + val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_CMP_ERR;
> + val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_LOGIC_ERR;
> + appl_writel(pcie, val, APPL_INTR_EN_L1_18);
> + }
> +
> + val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
> + PCI_EXP_LNKSTA);
> + pcie->init_link_width = (val_w & PCI_EXP_LNKSTA_NLW) >>
> + PCI_EXP_LNKSTA_NLW_SHIFT;
> +
> + val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
> + PCI_EXP_LNKCTL);
> + val_w |= PCI_EXP_LNKCTL_LBMIE;
> + dw_pcie_writew_dbi(&pcie->pci, pcie->pcie_cap_base + PCI_EXP_LNKCTL,
> + val_w);
> +}
> +
> +static void tegra_pcie_enable_legacy_interrupts(struct pcie_port *pp)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> + struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> + u32 val;
> +
> + /* Enable legacy interrupt generation */
> + val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> + val |= APPL_INTR_EN_L0_0_SYS_INTR_EN;
> + val |= APPL_INTR_EN_L0_0_INT_INT_EN;
> + appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +
> + val = appl_readl(pcie, APPL_INTR_EN_L1_8_0);
> + val |= APPL_INTR_EN_L1_8_INTX_EN;
> + val |= APPL_INTR_EN_L1_8_AUTO_BW_INT_EN;
> + val |= APPL_INTR_EN_L1_8_BW_MGT_INT_EN;
> + if (IS_ENABLED(CONFIG_PCIEAER))
> + val |= APPL_INTR_EN_L1_8_AER_INT_EN;
> + appl_writel(pcie, val, APPL_INTR_EN_L1_8_0);
> +}
> +
> +static void tegra_pcie_enable_msi_interrupts(struct pcie_port *pp)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> + struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> + u32 val;
> +
> + dw_pcie_msi_init(pp);
> +
> + /* Enable MSI interrupt generation */
> + val = appl_readl(pcie, APPL_INTR_EN_L0_0);
> + val |= APPL_INTR_EN_L0_0_SYS_MSI_INTR_EN;
> + val |= APPL_INTR_EN_L0_0_MSI_RCV_INT_EN;
> + appl_writel(pcie, val, APPL_INTR_EN_L0_0);
> +}
> +
> +static void tegra_pcie_enable_interrupts(struct pcie_port *pp)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> + struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> +
> + /* Clear interrupt statuses before enabling interrupts */
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L0);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_0_0);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_1);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_2);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_3);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_6);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_7);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_8_0);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_9);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_10);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_11);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_13);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_14);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_15);
> + appl_writel(pcie, 0xFFFFFFFF, APPL_INTR_STATUS_L1_17);
> +
> + tegra_pcie_enable_system_interrupts(pp);
> + tegra_pcie_enable_legacy_interrupts(pp);
> + if (IS_ENABLED(CONFIG_PCI_MSI))
> + tegra_pcie_enable_msi_interrupts(pp);
> +}
> +
> +static void config_gen3_gen4_eq_presets(struct tegra_pcie_dw *pcie)
> +{
> + struct dw_pcie *pci = &pcie->pci;
> + u32 val, offset, i;
> +
> + /* Program init preset */
> + for (i = 0; i < pcie->num_lanes; i++) {
> + dw_pcie_read(pci->dbi_base + CAP_SPCIE_CAP_OFF
> + + (i * 2), 2, &val);
> + val &= ~CAP_SPCIE_CAP_OFF_DSP_TX_PRESET0_MASK;
> + val |= GEN3_GEN4_EQ_PRESET_INIT;
> + val &= ~CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK;
> + val |= (GEN3_GEN4_EQ_PRESET_INIT <<
> + CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT);
> + dw_pcie_write(pci->dbi_base + CAP_SPCIE_CAP_OFF
> + + (i * 2), 2, val);
> +
> + offset = dw_pcie_find_ext_capability(pci,
> + PCI_EXT_CAP_ID_PL_16GT) +
> + PCI_PL_16GT_LE_CTRL;
> + dw_pcie_read(pci->dbi_base + offset + i, 1, &val);
> + val &= ~PCI_PL_16GT_LE_CTRL_DSP_TX_PRESET_MASK;
> + val |= GEN3_GEN4_EQ_PRESET_INIT;
> + val &= ~PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK;
> + val |= (GEN3_GEN4_EQ_PRESET_INIT <<
> + PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT);
> + dw_pcie_write(pci->dbi_base + offset + i, 1, val);
> + }
> +
> + val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> + val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> + dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +
> + val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
> + val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
> + val |= (0x3ff << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
> + val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
> + dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
> +
> + val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> + val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> + val |= (0x1 << GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT);
> + dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +
> + val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
> + val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
> + val |= (0x360 << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
> + val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
> + dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
> +
> + val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> + val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> + dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +}
> +
> +static int tegra_pcie_dw_host_init(struct pcie_port *pp)
> +{
> + struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> + struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> + u32 val, tmp, offset, speed;
> + unsigned int count;
> + u16 val_w;
> +
> +core_init:

I think it would be cleaner to include all registers programming
within a function and we remove this label (and goto) below.

> + count = 200;

It would be easier to read if we could inizialize this value closer
to where it is actually used. Actually explaining why 200 as value
was chosen would be appreciated.

> +#if defined(CONFIG_PCIEASPM)
> + offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS);
> + pcie->cfg_link_cap_l1sub = offset + PCI_L1SS_CAP;
> +#endif

Please try to factor this out within a single #ifdef guard.

> + val = dw_pcie_readl_dbi(pci, PCI_IO_BASE);
> + val &= ~(IO_BASE_IO_DECODE | IO_BASE_IO_DECODE_BIT8);
> + dw_pcie_writel_dbi(pci, PCI_IO_BASE, val);
> +
> + val = dw_pcie_readl_dbi(pci, PCI_PREF_MEMORY_BASE);
> + val |= CFG_PREF_MEM_LIMIT_BASE_MEM_DECODE;
> + val |= CFG_PREF_MEM_LIMIT_BASE_MEM_LIMIT_DECODE;
> + dw_pcie_writel_dbi(pci, PCI_PREF_MEMORY_BASE, val);
> +
> + dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);
> +
> + /* Configure FTS */
> + val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
> + val &= ~(N_FTS_MASK << N_FTS_SHIFT);
> + val |= N_FTS_VAL << N_FTS_SHIFT;
> + dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
> +
> + val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
> + val &= ~FTS_MASK;
> + val |= FTS_VAL;
> + dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
> +
> + /* Enable as 0xFFFF0001 response for CRS */
> + val = dw_pcie_readl_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT);
> + val &= ~(AMBA_ERROR_RESPONSE_CRS_MASK << AMBA_ERROR_RESPONSE_CRS_SHIFT);
> + val |= (AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001 <<
> + AMBA_ERROR_RESPONSE_CRS_SHIFT);
> + dw_pcie_writel_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT, val);
> +
> + /* Configure Max Speed from DT */
> + if (pcie->max_speed && pcie->max_speed != -EINVAL) {
> + val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base +
> + PCI_EXP_LNKCAP);
> + val &= ~PCI_EXP_LNKCAP_SLS;
> + val |= pcie->max_speed;
> + dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP,
> + val);
> + }
> +
> + /* Configure Max lane width from DT */
> + val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP);
> + val &= ~PCI_EXP_LNKCAP_MLW;
> + val |= (pcie->num_lanes << PCI_EXP_LNKSTA_NLW_SHIFT);
> + dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP, val);
> +
> + config_gen3_gen4_eq_presets(pcie);
> +
> +#if defined(CONFIG_PCIEASPM)
> + /* Enable ASPM counters */
> + val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> + val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> + dw_pcie_writel_dbi(pci, event_cntr_ctrl_offset[pcie->cid], val);
> +
> + /* Program T_cmrt and T_pwr_on values */
> + val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub);
> + val &= ~(PCI_L1SS_CAP_CM_RESTORE_TIME | PCI_L1SS_CAP_P_PWR_ON_VALUE);
> + val |= (pcie->aspm_cmrt << 8);
> + val |= (pcie->aspm_pwr_on_t << 19);
> + dw_pcie_writel_dbi(pci, pcie->cfg_link_cap_l1sub, val);
> +
> + /* Program L0s and L1 entrance latencies */
> + val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
> + val &= ~L0S_ENTRANCE_LAT_MASK;
> + val |= (pcie->aspm_l0s_enter_lat << L0S_ENTRANCE_LAT_SHIFT);
> + val |= ENTER_ASPM;
> + dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
> +#endif

See above.

> + val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> + val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
> + dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> +
> + if (pcie->update_fc_fixup) {
> + val = dw_pcie_readl_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF);
> + val |= 0x1 << CFG_TIMER_CTRL_ACK_NAK_SHIFT;
> + dw_pcie_writel_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF, val);
> + }
> +
> + dw_pcie_setup_rc(pp);
> +
> + clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);
> +
> + /* Assert RST */
> + val = appl_readl(pcie, APPL_PINMUX);
> + val &= ~APPL_PINMUX_PEX_RST;
> + appl_writel(pcie, val, APPL_PINMUX);
> +
> + usleep_range(100, 200);
> +
> + /* Enable LTSSM */
> + val = appl_readl(pcie, APPL_CTRL);
> + val |= APPL_CTRL_LTSSM_EN;
> + appl_writel(pcie, val, APPL_CTRL);
> +
> + /* De-assert RST */
> + val = appl_readl(pcie, APPL_PINMUX);
> + val |= APPL_PINMUX_PEX_RST;
> + appl_writel(pcie, val, APPL_PINMUX);
> +
> + msleep(100);
> +
> + val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> + while (!(val_w & PCI_EXP_LNKSTA_DLLLA)) {
> + if (count) {
> + dev_dbg(pci->dev, "Waiting for link up\n");
> + usleep_range(1000, 2000);
> + val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> + PCI_EXP_LNKSTA);
> + count--;
> + continue;
> + }
> +
> + val = appl_readl(pcie, APPL_DEBUG);
> + val &= APPL_DEBUG_LTSSM_STATE_MASK;
> + val >>= APPL_DEBUG_LTSSM_STATE_SHIFT;
> + tmp = appl_readl(pcie, APPL_LINK_STATUS);
> + tmp &= APPL_LINK_STATUS_RDLH_LINK_UP;
> + if (!(val == 0x11 && !tmp)) {
> + dev_info(pci->dev, "Link is down\n");
> + return 0;
> + }
> +
> + dev_info(pci->dev, "Link is down in DLL");
> + dev_info(pci->dev, "Trying again with DLFE disabled\n");
> + /* Disable LTSSM */
> + val = appl_readl(pcie, APPL_CTRL);
> + val &= ~APPL_CTRL_LTSSM_EN;
> + appl_writel(pcie, val, APPL_CTRL);
> +
> + reset_control_assert(pcie->core_rst);
> + reset_control_deassert(pcie->core_rst);
> +
> + offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_DLF);
> + val = dw_pcie_readl_dbi(pci, offset + PCI_DLF_CAP);
> + val &= ~PCI_DLF_EXCHANGE_ENABLE;
> + dw_pcie_writel_dbi(pci, offset, val);
> +
> + /* Retry now with DLF Exchange disabled */
> + goto core_init;

This goto upwards honestly is a bit horrible. Use some functions
to make the code more readable.

> + }
> + dev_dbg(pci->dev, "Link is up\n");
> +
> + speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
> + PCI_EXP_LNKSTA_CLS;
> + clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
> +
> + tegra_pcie_enable_interrupts(pp);
> +
> + return 0;
> +}
> +
> +static int tegra_pcie_dw_link_up(struct dw_pcie *pci)
> +{
> + struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> + u32 val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> +
> + return !!(val & PCI_EXP_LNKSTA_DLLLA);

It looks like this can be common code reusable by other DWC drivers ?

Not mandatory, just a hint.

> +}
> +
> +static void tegra_pcie_set_msi_vec_num(struct pcie_port *pp)
> +{
> + pp->num_vectors = MAX_MSI_IRQS;
> +}
> +
> +static const struct dw_pcie_ops tegra_dw_pcie_ops = {
> + .link_up = tegra_pcie_dw_link_up,
> +};
> +
> +static struct dw_pcie_host_ops tegra_pcie_dw_host_ops = {
> + .rd_own_conf = tegra_pcie_dw_rd_own_conf,
> + .wr_own_conf = tegra_pcie_dw_wr_own_conf,
> + .host_init = tegra_pcie_dw_host_init,
> + .set_num_vectors = tegra_pcie_set_msi_vec_num,
> +};
> +
> +static void tegra_pcie_disable_phy(struct tegra_pcie_dw *pcie)
> +{
> + unsigned int phy_count = pcie->phy_count;
> +
> + while (phy_count--) {
> + phy_power_off(pcie->phys[phy_count]);
> + phy_exit(pcie->phys[phy_count]);
> + }
> +}
> +
> +static int tegra_pcie_enable_phy(struct tegra_pcie_dw *pcie)
> +{
> + unsigned int i;
> + int ret;
> +
> + for (i = 0; i < pcie->phy_count; i++) {
> + ret = phy_init(pcie->phys[i]);
> + if (ret < 0)
> + goto phy_power_off;
> +
> + ret = phy_power_on(pcie->phys[i]);
> + if (ret < 0)
> + goto phy_exit;
> + }
> +
> + return 0;
> +
> +phy_power_off:
> + while (i--) {
> + phy_power_off(pcie->phys[i]);
> +phy_exit:
> + phy_exit(pcie->phys[i]);
> + }
> +
> + return ret;
> +}
> +
> +static int tegra_pcie_dw_parse_dt(struct tegra_pcie_dw *pcie)
> +{
> + struct device_node *np = pcie->dev->of_node;
> + int ret;
> +
> + ret = of_property_read_u32(np, "nvidia,aspm-cmrt-us", &pcie->aspm_cmrt);
> + if (ret < 0) {
> + dev_info(pcie->dev, "Failed to read ASPM T_cmrt: %d\n", ret);
> + return ret;
> + }
> +
> + ret = of_property_read_u32(np, "nvidia,aspm-pwr-on-t-us",
> + &pcie->aspm_pwr_on_t);
> + if (ret < 0)
> + dev_info(pcie->dev, "Failed to read ASPM Power On time: %d\n",
> + ret);
> +
> + ret = of_property_read_u32(np, "nvidia,aspm-l0s-entrance-latency-us",
> + &pcie->aspm_l0s_enter_lat);
> + if (ret < 0)
> + dev_info(pcie->dev,
> + "Failed to read ASPM L0s Entrance latency: %d\n", ret);
> +
> + ret = of_property_read_u32(np, "num-lanes", &pcie->num_lanes);
> + if (ret < 0) {
> + dev_err(pcie->dev, "Failed to read num-lanes: %d\n", ret);
> + return ret;
> + }
> +
> + pcie->max_speed = of_pci_get_max_link_speed(np);
> +
> + ret = of_property_read_u32_index(np, "nvidia,bpmp", 1, &pcie->cid);
> + if (ret) {
> + dev_err(pcie->dev, "Failed to read Controller-ID: %d\n", ret);
> + return ret;
> + }
> +
> + pcie->phy_count = of_property_count_strings(np, "phy-names");
> + if (pcie->phy_count < 0) {
> + dev_err(pcie->dev, "Failed to find PHY entries: %d\n",
> + pcie->phy_count);
> + return pcie->phy_count;
> + }
> +
> + if (of_property_read_bool(np, "nvidia,update-fc-fixup"))
> + pcie->update_fc_fixup = true;
> +
> + pcie->supports_clkreq =
> + of_property_read_bool(pcie->dev->of_node, "supports-clkreq");
> +
> + pcie->enable_cdm_check =
> + of_property_read_bool(np, "snps,enable-cdm-check");
> +
> + return 0;
> +}
> +
> +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
> + bool enable)
> +{
> + struct mrq_uphy_response resp;
> + struct tegra_bpmp_message msg;
> + struct mrq_uphy_request req;
> + int err;
> +
> + if (pcie->cid == 5)
> + return 0;

What's wrong with cid == 5 ? Explain please.

> + memset(&req, 0, sizeof(req));
> + memset(&resp, 0, sizeof(resp));
> +
> + req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
> + req.controller_state.pcie_controller = pcie->cid;
> + req.controller_state.enable = enable;
> +
> + memset(&msg, 0, sizeof(msg));
> + msg.mrq = MRQ_UPHY;
> + msg.tx.data = &req;
> + msg.tx.size = sizeof(req);
> + msg.rx.data = &resp;
> + msg.rx.size = sizeof(resp);
> +
> + if (irqs_disabled())

Can you explain to me what this check is meant to achieve please ?

> + err = tegra_bpmp_transfer_atomic(pcie->bpmp, &msg);
> + else
> + err = tegra_bpmp_transfer(pcie->bpmp, &msg);
> +
> + return err;
> +}
> +
> +static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie)
> +{
> + struct pcie_port *pp = &pcie->pci.pp;
> + struct pci_dev *pdev;
> + struct pci_bus *child;
> +
> + list_for_each_entry(child, &pp->root_bus->children, node) {
> + /* Bring downstream devices to D0 if they are not already in */
> + if (child->parent == pp->root_bus)
> + break;
> + }
> + list_for_each_entry(pdev, &child->devices, bus_list) {
> + if (PCI_SLOT(pdev->devfn) == 0) {
> + if (pci_set_power_state(pdev, PCI_D0))
> + dev_err(pcie->dev,
> + "Failed to transition %s to D0 state\n",
> + dev_name(&pdev->dev));
> + }
> + }
> +}
> +
> +static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie,
> + bool en_hw_hot_rst)
> +{
> + int ret;
> + u32 val;
> +
> + ret = tegra_pcie_bpmp_set_ctrl_state(pcie, true);
> + if (ret) {
> + dev_err(pcie->dev,
> + "Failed to enable controller %u: %d\n", pcie->cid, ret);
> + return ret;
> + }
> +
> + ret = regulator_enable(pcie->pex_ctl_supply);
> + if (ret < 0) {
> + dev_err(pcie->dev, "Failed to enable regulator: %d\n", ret);
> + goto fail_reg_en;
> + }
> +
> + ret = clk_prepare_enable(pcie->core_clk);
> + if (ret) {
> + dev_err(pcie->dev, "Failed to enable core clock: %d\n", ret);
> + goto fail_core_clk;
> + }
> +
> + ret = reset_control_deassert(pcie->core_apb_rst);
> + if (ret) {
> + dev_err(pcie->dev, "Failed to deassert core APB reset: %d\n",
> + ret);
> + goto fail_core_apb_rst;
> + }
> +
> + if (en_hw_hot_rst) {
> + /* Enable HW_HOT_RST mode */
> + val = appl_readl(pcie, APPL_CTRL);
> + val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> + APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> + val |= APPL_CTRL_HW_HOT_RST_EN;
> + appl_writel(pcie, val, APPL_CTRL);
> + }
> +
> + ret = tegra_pcie_enable_phy(pcie);
> + if (ret) {
> + dev_err(pcie->dev, "Failed to enable PHY: %d\n", ret);
> + goto fail_phy;
> + }
> +
> + /* Update CFG base address */
> + appl_writel(pcie, pcie->dbi_res->start & APPL_CFG_BASE_ADDR_MASK,
> + APPL_CFG_BASE_ADDR);
> +
> + /* Configure this core for RP mode operation */
> + appl_writel(pcie, APPL_DM_TYPE_RP, APPL_DM_TYPE);
> +
> + appl_writel(pcie, 0x0, APPL_CFG_SLCG_OVERRIDE);
> +
> + val = appl_readl(pcie, APPL_CTRL);
> + appl_writel(pcie, val | APPL_CTRL_SYS_PRE_DET_STATE, APPL_CTRL);
> +
> + val = appl_readl(pcie, APPL_CFG_MISC);
> + val |= (APPL_CFG_MISC_ARCACHE_VAL << APPL_CFG_MISC_ARCACHE_SHIFT);
> + appl_writel(pcie, val, APPL_CFG_MISC);
> +
> + if (!pcie->supports_clkreq) {
> + val = appl_readl(pcie, APPL_PINMUX);
> + val |= APPL_PINMUX_CLKREQ_OUT_OVRD_EN;
> + val |= APPL_PINMUX_CLKREQ_OUT_OVRD;
> + appl_writel(pcie, val, APPL_PINMUX);
> + }
> +
> + /* Update iATU_DMA base address */
> + appl_writel(pcie,
> + pcie->atu_dma_res->start & APPL_CFG_IATU_DMA_BASE_ADDR_MASK,
> + APPL_CFG_IATU_DMA_BASE_ADDR);
> +
> + reset_control_deassert(pcie->core_rst);
> +
> + pcie->pcie_cap_base = dw_pcie_find_capability(&pcie->pci,
> + PCI_CAP_ID_EXP);
> +
> +#if defined(CONFIG_PCIEASPM)
> + /* Disable ASPM-L1SS advertisement as there is no CLKREQ routing */
> + if (!pcie->supports_clkreq) {
> + disable_aspm_l11(pcie);
> + disable_aspm_l12(pcie);
> + }
> +#endif
> + return ret;
> +
> +fail_phy:
> + reset_control_assert(pcie->core_apb_rst);
> +fail_core_apb_rst:
> + clk_disable_unprepare(pcie->core_clk);
> +fail_core_clk:
> + regulator_disable(pcie->pex_ctl_supply);
> +fail_reg_en:
> + tegra_pcie_bpmp_set_ctrl_state(pcie, false);
> +
> + return ret;
> +}
> +
> +static int __deinit_controller(struct tegra_pcie_dw *pcie)
> +{
> + int ret;
> +
> + ret = reset_control_assert(pcie->core_rst);
> + if (ret) {
> + dev_err(pcie->dev, "Failed to assert \"core\" reset: %d\n",
> + ret);
> + return ret;
> + }
> + tegra_pcie_disable_phy(pcie);
> + ret = reset_control_assert(pcie->core_apb_rst);
> + if (ret) {
> + dev_err(pcie->dev, "Failed to assert APB reset: %d\n", ret);
> + return ret;
> + }
> + clk_disable_unprepare(pcie->core_clk);
> + ret = regulator_disable(pcie->pex_ctl_supply);
> + if (ret) {
> + dev_err(pcie->dev, "Failed to disable regulator: %d\n", ret);
> + return ret;
> + }
> + ret = tegra_pcie_bpmp_set_ctrl_state(pcie, false);
> + if (ret) {
> + dev_err(pcie->dev, "Failed to disable controller %d: %d\n",
> + pcie->cid, ret);
> + return ret;
> + }
> + return ret;
> +}
> +
> +static int tegra_pcie_init_controller(struct tegra_pcie_dw *pcie)
> +{
> + struct dw_pcie *pci = &pcie->pci;
> + struct pcie_port *pp = &pci->pp;
> + int ret;
> +
> + ret = tegra_pcie_config_controller(pcie, false);
> + if (ret < 0)
> + return ret;
> +
> + pp->root_bus_nr = -1;
> + pp->ops = &tegra_pcie_dw_host_ops;
> +
> + ret = dw_pcie_host_init(pp);
> + if (ret < 0) {
> + dev_err(pcie->dev, "Failed to add PCIe port: %d\n", ret);
> + goto fail_host_init;
> + }
> +
> + return 0;
> +
> +fail_host_init:
> + return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_try_link_l2(struct tegra_pcie_dw *pcie)
> +{
> + u32 val;
> +
> + if (!tegra_pcie_dw_link_up(&pcie->pci))
> + return 0;
> +
> + val = appl_readl(pcie, APPL_RADM_STATUS);
> + val |= APPL_PM_XMT_TURNOFF_STATE;
> + appl_writel(pcie, val, APPL_RADM_STATUS);
> +
> + return readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG, val,
> + val & APPL_DEBUG_PM_LINKST_IN_L2_LAT,
> + 1, PME_ACK_TIMEOUT);
> +}
> +
> +static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie)
> +{
> + u32 data;
> + int err;
> +
> + if (!tegra_pcie_dw_link_up(&pcie->pci)) {
> + dev_dbg(pcie->dev, "PCIe link is not up...!\n");
> + return;
> + }
> +
> + if (tegra_pcie_try_link_l2(pcie)) {
> + dev_info(pcie->dev, "Link didn't transition to L2 state\n");
> + /*
> + * TX lane clock freq will reset to Gen1 only if link is in L2
> + * or detect state.
> + * So apply pex_rst to end point to force RP to go into detect
> + * state
> + */
> + data = appl_readl(pcie, APPL_PINMUX);
> + data &= ~APPL_PINMUX_PEX_RST;
> + appl_writel(pcie, data, APPL_PINMUX);
> +
> + err = readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG,
> + data,
> + ((data &
> + APPL_DEBUG_LTSSM_STATE_MASK) >>
> + APPL_DEBUG_LTSSM_STATE_SHIFT) ==
> + LTSSM_STATE_PRE_DETECT,
> + 1, LTSSM_TIMEOUT);
> + if (err) {
> + dev_info(pcie->dev, "Link didn't go to detect state\n");
> + } else {
> + /* Disable LTSSM after link is in detect state */
> + data = appl_readl(pcie, APPL_CTRL);
> + data &= ~APPL_CTRL_LTSSM_EN;
> + appl_writel(pcie, data, APPL_CTRL);
> + }
> + }
> + /*
> + * DBI registers may not be accessible after this as PLL-E would be
> + * down depending on how CLKREQ is pulled by end point
> + */
> + data = appl_readl(pcie, APPL_PINMUX);
> + data |= (APPL_PINMUX_CLKREQ_OVERRIDE_EN | APPL_PINMUX_CLKREQ_OVERRIDE);
> + /* Cut REFCLK to slot */
> + data |= APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE_EN;
> + data &= ~APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE;
> + appl_writel(pcie, data, APPL_PINMUX);
> +}
> +
> +static int tegra_pcie_deinit_controller(struct tegra_pcie_dw *pcie)
> +{
> + /*
> + * link doesn't go into L2 state with some of the endpoints with Tegra
> + * if they are not in D0 state. So, need to make sure that immediate
> + * downstream devices are in D0 state before sending PME_TurnOff to put
> + * link into L2 state
> + */
> + tegra_pcie_downstream_dev_to_D0(pcie);
> + dw_pcie_host_deinit(&pcie->pci.pp);
> + tegra_pcie_dw_pme_turnoff(pcie);
> + return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
> +{
> + struct pcie_port *pp = &pcie->pci.pp;
> + struct device *dev = pcie->dev;
> + char *name;
> + int ret;
> +
> + if (IS_ENABLED(CONFIG_PCI_MSI)) {
> + pp->msi_irq = of_irq_get_byname(dev->of_node, "msi");
> + if (!pp->msi_irq) {
> + dev_err(dev, "Failed to get MSI interrupt\n");
> + return -ENODEV;
> + }
> + }
> +
> + pm_runtime_enable(dev);
> + ret = pm_runtime_get_sync(dev);
> + if (ret < 0) {
> + dev_err(dev, "Failed to get runtime sync for PCIe dev: %d\n",
> + ret);
> + pm_runtime_disable(dev);
> + return ret;
> + }
> +
> + tegra_pcie_init_controller(pcie);
> +
> + pcie->link_state = tegra_pcie_dw_link_up(&pcie->pci);
> +
> + if (!pcie->link_state) {
> + ret = -ENOMEDIUM;
> + goto fail_host_init;
> + }
> +
> + name = devm_kasprintf(dev, GFP_KERNEL, "%pOFP", dev->of_node);
> + if (!name) {
> + ret = -ENOMEM;
> + goto fail_host_init;
> + }
> +
> + pcie->debugfs = debugfs_create_dir(name, NULL);
> + if (!pcie->debugfs)
> + dev_err(dev, "Failed to create debugfs\n");
> + else
> + init_debugfs(pcie);
> +
> + return ret;
> +
> +fail_host_init:
> + tegra_pcie_deinit_controller(pcie);
> + pm_runtime_put_sync(dev);
> + pm_runtime_disable(dev);
> + return ret;
> +}
> +
> +static const struct tegra_pcie_soc tegra_pcie_rc_of_data = {
> + .mode = DW_PCIE_RC_TYPE,
> +};
> +
> +static const struct of_device_id tegra_pcie_dw_of_match[] = {
> + {
> + .compatible = "nvidia,tegra194-pcie",
> + .data = &tegra_pcie_rc_of_data,
> + },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, tegra_pcie_dw_of_match);
> +
> +static int tegra_pcie_dw_probe(struct platform_device *pdev)
> +{
> + const struct tegra_pcie_soc *data;
> + struct device *dev = &pdev->dev;
> + struct resource *atu_dma_res;
> + struct tegra_pcie_dw *pcie;
> + struct resource *dbi_res;
> + struct pcie_port *pp;
> + struct dw_pcie *pci;
> + struct phy **phys;
> + char *name;
> + int ret;
> + u32 i;
> +
> + pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> + if (!pcie)
> + return -ENOMEM;
> +
> + pci = &pcie->pci;
> + pci->dev = &pdev->dev;
> + pci->ops = &tegra_dw_pcie_ops;
> + pp = &pci->pp;
> + pcie->dev = &pdev->dev;
> +
> + data = (struct tegra_pcie_soc *)of_device_get_match_data(dev);
> + if (!data)
> + return -EINVAL;
> + pcie->mode = (enum dw_pcie_device_mode)data->mode;
> +
> + ret = tegra_pcie_dw_parse_dt(pcie);
> + if (ret < 0) {
> + dev_err(dev, "Failed to parse device tree: %d\n", ret);
> + return ret;
> + }
> +
> + pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl");
> + if (IS_ERR(pcie->pex_ctl_supply)) {
> + dev_err(dev, "Failed to get regulator: %ld\n",
> + PTR_ERR(pcie->pex_ctl_supply));
> + return PTR_ERR(pcie->pex_ctl_supply);
> + }
> +
> + pcie->core_clk = devm_clk_get(dev, "core");
> + if (IS_ERR(pcie->core_clk)) {
> + dev_err(dev, "Failed to get core clock: %ld\n",
> + PTR_ERR(pcie->core_clk));
> + return PTR_ERR(pcie->core_clk);
> + }
> +
> + pcie->appl_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> + "appl");
> + if (!pcie->appl_res) {
> + dev_err(dev, "Failed to find \"appl\" region\n");
> + return PTR_ERR(pcie->appl_res);
> + }
> + pcie->appl_base = devm_ioremap_resource(dev, pcie->appl_res);
> + if (IS_ERR(pcie->appl_base))
> + return PTR_ERR(pcie->appl_base);
> +
> + pcie->core_apb_rst = devm_reset_control_get(dev, "apb");
> + if (IS_ERR(pcie->core_apb_rst)) {
> + dev_err(dev, "Failed to get APB reset: %ld\n",
> + PTR_ERR(pcie->core_apb_rst));
> + return PTR_ERR(pcie->core_apb_rst);
> + }
> +
> + phys = devm_kcalloc(dev, pcie->phy_count, sizeof(*phys), GFP_KERNEL);
> + if (!phys)
> + return PTR_ERR(phys);
> +
> + for (i = 0; i < pcie->phy_count; i++) {
> + name = kasprintf(GFP_KERNEL, "p2u-%u", i);
> + if (!name) {
> + dev_err(dev, "Failed to create P2U string\n");
> + return -ENOMEM;
> + }
> + phys[i] = devm_phy_get(dev, name);
> + kfree(name);
> + if (IS_ERR(phys[i])) {
> + ret = PTR_ERR(phys[i]);
> + dev_err(dev, "Failed to get PHY: %d\n", ret);
> + return ret;
> + }
> + }
> +
> + pcie->phys = phys;
> +
> + dbi_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> + if (!dbi_res) {
> + dev_err(dev, "Failed to find \"dbi\" region\n");
> + return PTR_ERR(dbi_res);
> + }
> + pcie->dbi_res = dbi_res;
> +
> + pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
> + if (IS_ERR(pci->dbi_base))
> + return PTR_ERR(pci->dbi_base);
> +
> + /* Tegra HW locates DBI2 at a fixed offset from DBI */
> + pci->dbi_base2 = pci->dbi_base + 0x1000;
> +
> + atu_dma_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> + "atu_dma");
> + if (!atu_dma_res) {
> + dev_err(dev, "Failed to find \"atu_dma\" region\n");
> + return PTR_ERR(atu_dma_res);
> + }
> + pcie->atu_dma_res = atu_dma_res;
> + pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
> + if (IS_ERR(pci->atu_base))
> + return PTR_ERR(pci->atu_base);
> +
> + pcie->core_rst = devm_reset_control_get(dev, "core");
> + if (IS_ERR(pcie->core_rst)) {
> + dev_err(dev, "Failed to get core reset: %ld\n",
> + PTR_ERR(pcie->core_rst));
> + return PTR_ERR(pcie->core_rst);
> + }
> +
> + pp->irq = platform_get_irq_byname(pdev, "intr");
> + if (!pp->irq) {
> + dev_err(dev, "Failed to get \"intr\" interrupt\n");
> + return -ENODEV;
> + }
> +
> + ret = devm_request_irq(dev, pp->irq, tegra_pcie_irq_handler,
> + IRQF_SHARED, "tegra-pcie-intr", pcie);
> + if (ret) {
> + dev_err(dev, "Failed to request IRQ %d: %d\n", pp->irq, ret);
> + return ret;
> + }
> +
> + pcie->bpmp = tegra_bpmp_get(dev);
> + if (IS_ERR(pcie->bpmp))
> + return PTR_ERR(pcie->bpmp);
> +
> + platform_set_drvdata(pdev, pcie);
> +
> + if (pcie->mode == DW_PCIE_RC_TYPE) {
> + ret = tegra_pcie_config_rp(pcie);
> + if (ret && ret != -ENOMEDIUM)
> + goto fail;
> + else
> + return 0;

So if the link is not up we still go ahead and make probe
succeed. What for ?

> + }
> +
> +fail:
> + tegra_bpmp_put(pcie->bpmp);
> + return ret;
> +}
> +
> +static int tegra_pcie_dw_remove(struct platform_device *pdev)
> +{
> + struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
> +
> + if (pcie->mode != DW_PCIE_RC_TYPE)
> + return 0;
> +
> + if (!pcie->link_state)
> + return 0;
> +
> + debugfs_remove_recursive(pcie->debugfs);
> + tegra_pcie_deinit_controller(pcie);
> + pm_runtime_put_sync(pcie->dev);
> + pm_runtime_disable(pcie->dev);
> + tegra_bpmp_put(pcie->bpmp);
> +
> + return 0;
> +}
> +
> +static int tegra_pcie_dw_suspend_late(struct device *dev)
> +{
> + struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> + u32 val;
> +
> + if (!pcie->link_state)
> + return 0;
> +
> + /* Enable HW_HOT_RST mode */
> + val = appl_readl(pcie, APPL_CTRL);
> + val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> + APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> + val |= APPL_CTRL_HW_HOT_RST_EN;
> + appl_writel(pcie, val, APPL_CTRL);
> +
> + return 0;
> +}
> +
> +static int tegra_pcie_dw_suspend_noirq(struct device *dev)
> +{
> + struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> +
> + if (!pcie->link_state)
> + return 0;
> +
> + /* Save MSI interrupt vector */
> + pcie->msi_ctrl_int = dw_pcie_readl_dbi(&pcie->pci,
> + PORT_LOGIC_MSI_CTRL_INT_0_EN);
> + tegra_pcie_downstream_dev_to_D0(pcie);

I think this requires some comments. AFAIU this is allowed by
the PCI specs (PCI Express Base 4.0 r1.0 September 29-2017,
5.2 Link State Power Management). However, I would like to
understand how this plays with the D state the devices are left
in upon system suspend.

"As the following example illustrates, it is also possible to remove
power without first placing all Functions into D3Hot".

I assume that's what happens on this platform to allow L2 entry but
again, this needs clarification.

Lorenzo

> + tegra_pcie_dw_pme_turnoff(pcie);
> + return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_dw_resume_noirq(struct device *dev)
> +{
> + struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> + int ret;
> +
> + if (!pcie->link_state)
> + return 0;
> +
> + ret = tegra_pcie_config_controller(pcie, true);
> + if (ret < 0)
> + return ret;
> +
> + ret = tegra_pcie_dw_host_init(&pcie->pci.pp);
> + if (ret < 0) {
> + dev_err(dev, "Failed to init host: %d\n", ret);
> + goto fail_host_init;
> + }
> +
> + /* Restore MSI interrupt vector */
> + dw_pcie_writel_dbi(&pcie->pci, PORT_LOGIC_MSI_CTRL_INT_0_EN,
> + pcie->msi_ctrl_int);
> +
> + return 0;
> +fail_host_init:
> + return __deinit_controller(pcie);
> +}
> +
> +static int tegra_pcie_dw_resume_early(struct device *dev)
> +{
> + struct tegra_pcie_dw *pcie = dev_get_drvdata(dev);
> + u32 val;
> +
> + if (!pcie->link_state)
> + return 0;
> +
> + /* Disable HW_HOT_RST mode */
> + val = appl_readl(pcie, APPL_CTRL);
> + val &= ~(APPL_CTRL_HW_HOT_RST_MODE_MASK <<
> + APPL_CTRL_HW_HOT_RST_MODE_SHIFT);
> + val |= APPL_CTRL_HW_HOT_RST_MODE_IMDT_RST <<
> + APPL_CTRL_HW_HOT_RST_MODE_SHIFT;
> + val &= ~APPL_CTRL_HW_HOT_RST_EN;
> + appl_writel(pcie, val, APPL_CTRL);
> +
> + return 0;
> +}
> +
> +static void tegra_pcie_dw_shutdown(struct platform_device *pdev)
> +{
> + struct tegra_pcie_dw *pcie = platform_get_drvdata(pdev);
> +
> + if (pcie->mode != DW_PCIE_RC_TYPE)
> + return;
> +
> + if (!pcie->link_state)
> + return;
> +
> + debugfs_remove_recursive(pcie->debugfs);
> + tegra_pcie_downstream_dev_to_D0(pcie);
> +
> + disable_irq(pcie->pci.pp.irq);
> + if (IS_ENABLED(CONFIG_PCI_MSI))
> + disable_irq(pcie->pci.pp.msi_irq);
> +
> + tegra_pcie_dw_pme_turnoff(pcie);
> + __deinit_controller(pcie);
> +}
> +
> +static const struct dev_pm_ops tegra_pcie_dw_pm_ops = {
> + .suspend_late = tegra_pcie_dw_suspend_late,
> + .suspend_noirq = tegra_pcie_dw_suspend_noirq,
> + .resume_noirq = tegra_pcie_dw_resume_noirq,
> + .resume_early = tegra_pcie_dw_resume_early,
> +};
> +
> +static struct platform_driver tegra_pcie_dw_driver = {
> + .probe = tegra_pcie_dw_probe,
> + .remove = tegra_pcie_dw_remove,
> + .shutdown = tegra_pcie_dw_shutdown,
> + .driver = {
> + .name = "tegra194-pcie",
> + .pm = &tegra_pcie_dw_pm_ops,
> + .of_match_table = tegra_pcie_dw_of_match,
> + },
> +};
> +module_platform_driver(tegra_pcie_dw_driver);
> +
> +MODULE_AUTHOR("Vidya Sagar <vidyas@nvidia.com>");
> +MODULE_DESCRIPTION("NVIDIA PCIe host controller driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.17.1
>

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